This invention relates generally to food service equipment and more particularly to equipment for maintaining foods at temperatures suitable for serving food.
In one embodiment, this invention is especially (but not exclusively) directed to food service equipment that uses infrared (IR) heaters to maintain pre-cooked food at proper temperatures before serving. This type of equipment is referred to using such terms as holding oven, holding unit, and food warmer, and these terms are used interchangeably hereinafter. Such equipment is often used in, for example, the fast food service industry to heat food. However, such equipment has certain disadvantages. For example, short holding times (e.g., twenty minutes or less) and rapid product quality degradation often limit the effectiveness of this technology for holding applications. Additionally, different food products require different amounts of IR energy to be held in optimum condition. The quality of the food being held is affected in large part by the temperature and the air flow in the holding oven. As the food loses moisture due to evaporation, flavor is lost. This affects the texture and taste of the product. For example, chicken meat fibers will dry out and become tough, while the breading will become dry and greasy. French fries will develop a dry, rubbery texture as moisture is lost and the outer skin loses its crispness.
Conventional IR holding devices are not adjustable to control the amount of IR energy delivered to the food being heated. Rather, the heat source is on full power all of the time, and the food is placed relatively far from the heat source to prevent overheating. As a result, the typical prior holding device requires a large amount of vertical space. This can present a problem in a situation where space is at a premium, as in a fast-food restaurant.
U.S. Pat. Nos. 6,175,099, 6,262,394 and 6,541,739, assigned to Duke Manufacturing Co. of St. Louis, Mo. and incorporated herein by reference, are directed to a holding or cooking oven which is an improvement over prior designs and which has proven to be successful with various fried products. Relevant technology is also disclosed in pending U.S. application Ser. No. 10/680,626, filed Oct. 7, 2003, and in pending U.S. application Ser. No. 10/611,295, filed Jul. 1, 2003, which applications are also assigned to Duke Manufacturing Co. Each of the above-referenced patents and pending applications are incorporated herein by reference for all purposes not inconsistent with this disclosure.
Some food holding units (e.g., units for heating and/or cooling food) have multiple compartments each of which is adapted for holding a quantity of food. In such units, it is possible that heat transfer between adjacent compartments can have an adverse affect on food quality. There is a need, therefore, to compensate for such heat transfer. Further, where food is heated to higher temperatures, there is a need to prevent overheating of the food, any food-holding trays, and components of the unit.